ocaml/runtime/alloc.c

/**************************************************************************/
/*                                                                        */
/*                                 OCaml                                  */
/*                                                                        */
/*          Xavier Leroy and Damien Doligez, INRIA Rocquencourt           */
/*                                                                        */
/*   Copyright 1996 Institut National de Recherche en Informatique et     */
/*     en Automatique.                                                    */
/*                                                                        */
/*   All rights reserved.  This file is distributed under the terms of    */
/*   the GNU Lesser General Public License version 2.1, with the          */
/*   special exception on linking described in the file LICENSE.          */
/*                                                                        */
/**************************************************************************/

#define CAML_INTERNALS

/* 1. Allocation functions doing the same work as the macros in the
      case where [Setup_for_gc] and [Restore_after_gc] are no-ops.
   2. Convenience functions related to allocation.
*/

#include <string.h>
#include "caml/alloc.h"
#include "caml/custom.h"
#include "caml/major_gc.h"
#include "caml/memory.h"
#include "caml/mlvalues.h"
#include "caml/stacks.h"
#include "caml/signals.h"

#define Setup_for_gc
#define Restore_after_gc

CAMLexport value caml_alloc (mlsize_t wosize, tag_t tag)
{
  value result;
  mlsize_t i;

  CAMLassert (tag < 256);
  CAMLassert (tag != Infix_tag);
  if (wosize <= Max_young_wosize){
    if (wosize == 0){
      result = Atom (tag);
    }else{
      Alloc_small (result, wosize, tag);
      if (tag < No_scan_tag){
        for (i = 0; i < wosize; i++) Field (result, i) = Val_unit;
      }
    }
  }else{
    result = caml_alloc_shr (wosize, tag);
    if (tag < No_scan_tag){
      for (i = 0; i < wosize; i++) Field (result, i) = Val_unit;
    }
    result = caml_check_urgent_gc (result);
  }
  return result;
}

CAMLexport value caml_alloc_small (mlsize_t wosize, tag_t tag)
{
  value result;

  CAMLassert (wosize > 0);
  CAMLassert (wosize <= Max_young_wosize);
  CAMLassert (tag < 256);
  Alloc_small (result, wosize, tag);
  return result;
}

/* [n] is a number of words (fields) */
CAMLexport value caml_alloc_tuple(mlsize_t n)
{
  return caml_alloc(n, 0);
}

/* [len] is a number of bytes (chars) */
CAMLexport value caml_alloc_string (mlsize_t len)
{
  value result;
  mlsize_t offset_index;
  mlsize_t wosize = (len + sizeof (value)) / sizeof (value);

  if (wosize <= Max_young_wosize) {
    Alloc_small (result, wosize, String_tag);
  }else{
    result = caml_alloc_shr (wosize, String_tag);
    result = caml_check_urgent_gc (result);
  }
  Field (result, wosize - 1) = 0;
  offset_index = Bsize_wsize (wosize) - 1;
  Byte (result, offset_index) = offset_index - len;
  return result;
}

/* [len] is a number of bytes (chars) */
CAMLexport value caml_alloc_initialized_string (mlsize_t len, const char *p)
{
  value result = caml_alloc_string (len);
  memcpy((char *)String_val(result), p, len);
  return result;
}

/* [len] is a number of words.
   [mem] and [max] are relative (without unit).
*/
CAMLexport value caml_alloc_final (mlsize_t len, final_fun fun,
                                   mlsize_t mem, mlsize_t max)
{
  return caml_alloc_custom(caml_final_custom_operations(fun),
                           len * sizeof(value), mem, max);
}

CAMLexport value caml_copy_string(char const *s)
{
  mlsize_t len;
  value res;

  len = strlen(s);
  res = caml_alloc_initialized_string(len, s);
  return res;
}

CAMLexport value caml_alloc_array(value (*funct)(char const *),
                                  char const ** arr)
{
  CAMLparam0 ();
  mlsize_t nbr, n;
  CAMLlocal2 (v, result);

  nbr = 0;
  while (arr[nbr] != 0) nbr++;
  result = caml_alloc (nbr, 0);
  for (n = 0; n < nbr; n++) {
    /* The two statements below must be separate because of evaluation
       order (don't take the address &Field(result, n) before
       calling funct, which may cause a GC and move result). */
    v = funct(arr[n]);
    caml_modify(&Field(result, n), v);
  }
  CAMLreturn (result);
}

/* [len] is a number of floats */
value caml_alloc_float_array(mlsize_t len)
{
#ifdef FLAT_FLOAT_ARRAY
  mlsize_t wosize = len * Double_wosize;
  value result;
  /* For consistency with [caml_make_vect], which can't tell whether it should
     create a float array or not when the size is zero, the tag is set to
     zero when the size is zero. */
  if (wosize <= Max_young_wosize){
    if (wosize == 0)
      return Atom(0);
    else
      Alloc_small (result, wosize, Double_array_tag);
  }else {
    result = caml_alloc_shr (wosize, Double_array_tag);
    result = caml_check_urgent_gc (result);
  }
  return result;
#else
  return caml_alloc (len, 0);
#endif
}


CAMLexport value caml_copy_string_array(char const ** arr)
{
  return caml_alloc_array(caml_copy_string, arr);
}

CAMLexport int caml_convert_flag_list(value list, int *flags)
{
  int res;
  res = 0;
  while (list != Val_int(0)) {
    res |= flags[Int_val(Field(list, 0))];
    list = Field(list, 1);
  }
  return res;
}

/* For compiling let rec over values */

/* [size] is a [value] representing number of words (fields) */
CAMLprim value caml_alloc_dummy(value size)
{
  mlsize_t wosize = Long_val(size);
  return caml_alloc (wosize, 0);
}

/* [size] is a [value] representing number of words (fields) */
CAMLprim value caml_alloc_dummy_function(value size,value arity)
{
  /* the arity argument is used by the js_of_ocaml runtime */
  return caml_alloc_dummy(size);
}

/* [size] is a [value] representing number of floats. */
CAMLprim value caml_alloc_dummy_float (value size)
{
  mlsize_t wosize = Long_val(size) * Double_wosize;
  return caml_alloc (wosize, 0);
}

CAMLprim value caml_alloc_dummy_infix(value vsize, value voffset)
{
  mlsize_t wosize = Long_val(vsize), offset = Long_val(voffset);
  value v = caml_alloc(wosize, Closure_tag);
  /* The following choice of closure info causes the GC to skip
     the whole block contents.  This is correct since the dummy
     block contains no pointers into the heap.  However, the block
     cannot be marshaled or hashed, because not all closinfo fields
     and infix header fields are correctly initialized. */
  Closinfo_val(v) = Make_closinfo(0, wosize);
  if (offset > 0) {
    v += Bsize_wsize(offset);
    Hd_val(v) = Make_header(offset, Infix_tag, Caml_white);
  }
  return v;
}

CAMLprim value caml_update_dummy(value dummy, value newval)
{
  mlsize_t size, i;
  tag_t tag;

  tag = Tag_val (newval);

  if (tag == Double_array_tag){
    CAMLassert (Wosize_val(newval) == Wosize_val(dummy));
    CAMLassert (Tag_val(dummy) != Infix_tag);
    Tag_val(dummy) = Double_array_tag;
    size = Wosize_val (newval) / Double_wosize;
    for (i = 0; i < size; i++) {
      Store_double_flat_field (dummy, i, Double_flat_field (newval, i));
    }
  } else if (tag == Infix_tag) {
    value clos = newval - Infix_offset_hd(Hd_val(newval));
    CAMLassert (Tag_val(clos) == Closure_tag);
    CAMLassert (Tag_val(dummy) == Infix_tag);
    CAMLassert (Infix_offset_val(dummy) == Infix_offset_val(newval));
    dummy = dummy - Infix_offset_val(dummy);
    size = Wosize_val(clos);
    CAMLassert (size == Wosize_val(dummy));
    /* It is safe to use [caml_modify] to copy code pointers
       from [clos] to [dummy], because the value being overwritten is
       an integer, and the new "value" is a pointer outside the minor
       heap. */
    for (i = 0; i < size; i++) {
      caml_modify (&Field(dummy, i), Field(clos, i));
    }
  } else {
    CAMLassert (tag < No_scan_tag);
    CAMLassert (Tag_val(dummy) != Infix_tag);
    Tag_val(dummy) = tag;
    size = Wosize_val(newval);
    CAMLassert (size == Wosize_val(dummy));
    /* See comment above why this is safe even if [tag == Closure_tag]
       and some of the "values" being copied are actually code pointers. */
    for (i = 0; i < size; i++){
      caml_modify (&Field(dummy, i), Field(newval, i));
    }
  }
  return Val_unit;
}

CAMLexport value caml_alloc_some(value v)
{
  CAMLparam1(v);
  value some = caml_alloc_small(1, 0);
  Field(some, 0) = v;
  CAMLreturn(some);
}